Simple inspection device for analyzer for ionic activity measurement

ABSTRACT

A simple inspection device is constituted for inspection of an analyzer for measuring ionic activity by using an ionic activity measuring device provided with at least one ion selective electrode pair for generating an electrical potential corresponding to ionic activity of a predetermined ion, and a porous bridge for associating the electrodes of the ion selective electrode pair with each other, and by contacting potential difference measuring probes respectively with the electrodes of the ion selective electrode pair, to thereby measure a difference in potential between the electrodes. The simple inspection device employs a supporting member having outer dimensions approximately equal to the outer dimensions of the ionic activity measuring device, and an electrically conductive member supported on the supporting member for short-circuiting across the potential difference measuring probes when the potential difference measuring probes are contacted with the electrically conductive member.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a device for inspecting the functions of ananalyzer used for quantitatively analyzing the activity or concentrationof a specific ion contained in an aqueous liquid sample, for example, aliquor, a beverage, service water, and in particular a body fluid(blood, urine, saliva or the like), by potentiometry using of a slidetype ionic activity measuring device.

2. Description of the Prior Art

As disclosed in, for example, Japanese Patent Publication No.58(1983)-4981, and Japanese Unexamined Patent Publication Nos.58(1983)-156848 and 58(1983)-211648, there has been proposed a slidetype ionic activity measuring device for receiving a liquid sample fedin drops and measuring the activity of a specific ion contained in thesample.

The slide type ionic activity measuring device (hereinafter oftenreferred to as a slide) comprises at least one ion selective electrodepair consisting of ion selective electrodes generating a potentialcorresponding to the ionic activity of a predetermined ion, and a porousbridge disposed for communication between the electrodes of the ionselective electrode pair. A reference solution containing apredetermined ion whose ionic activity is known is applied to one of theelectrodes of the ion selective electrode pair, and sample solutionwhose ionic activity is unknown is applied to the other of the ionselective electrode pair. By the effect of the porous bridge, thereference solution and the sample solution contact each other to achievea liquid-junction, thus electrical conduction, therebetween. As aresult, a difference in potential corresponding to the difference inionic activity between the reference solution and the sample solutionarises between the electrodes of the ion selective electrode pair. Bymeasurement of the difference in potential, the activity of the specificion contained in the sample solution can be determined on the basis of acalibration curve determined in advance (by use of the Nernst equation).

In order to measure the ionic activity by use of the aforesaid slidetype ionic activity measuring device, an analyzer which applies areference solution and a sample solution and measures of a difference inpotential should preferably be used. Such an analyzer is described in,for example, U.S. Pat. No. 4,257,862 and Japanese Patent Application No.59(1984)-12794. The conventional analyzer of this type is constituted tosend the slide type ionic activity measuring device to a potentialmeasuring section after the application of the reference solution andthe sample solution, and to contact potential measuring probesrespectively with the electrodes of the aforesaid electrode pair at thepotential measuring section, to thereby measure the difference inpotential between the electrodes.

In the course of manufacture and usage of the analyzer having thearrangement as mentioned above, it is necessary to inspect whether theanalyzer is or is not capable of operating normally. Specifically, forexample, the manufacturer must carry out a delivery inspection and otherinspections, and the serviceman and the user must inspect the analyzerfor maintenance and confirmation of measured values.

As in the case of various other measuring apparatuses, the aforesaidinspection can be achieved electrically by use of a tester or the like.

However, it is troublesome to use a tester or the like for the aforesaidinspection. Also, in some cases, the serviceman or the user must carrythe tester or the like with him. In such cases, it is even moretroublesome to carry out the inspection by use of the tester or thelike.

SUMMARY OF THE INVENTION

The primary object of the present invention is to provide a simpleinspection device for a simple determination of whether an analyzer forionic activity measurement is or is not capable of operating normally.

Another object of the present invention is to provide a simpleinspection device for an analyzer for ionic activity measurement, whichis suitable for carrying out inspections of the analyzer simply andefficiently in the course of manufacture, maintenance and usage of theanalyzer.

The present invention provides a simple inspection device for ananalyzer for ionic activity measurement, which is used for inspectingthe functions of the analyzer for measuring ionic activity by using anionic activity measuring device provided with at least one ion selectiveelectrode pair for generating an electric potential corresponding toionic activity of a specific ion, and a porous bridge disposed toassociate the electrodes of the ion selective electrode pair with eachother, and by contacting potential difference measuring probesrespectively with the electrodes of the ion selective electrode pair, tothereby measure a difference in potential between the electrodes, thesimple inspection device for an analyzer for ionic activity measurementcomprising:

(i) a supporting member having outer dimensions approximately equal tothe outer dimensions of said ionic activity measuring device, and

(ii) an electrically conductive member supported on said supportingmember for short-circuiting across said potential difference measuringprobes when said potential difference measuring probes are contactedwith said electrically conductive member.

The present invention also provides a simple inspection device for ananalyzer for ionic activity measurement, wherein instead of theaforesaid electrically conductive member, a pair of electricalconductors of high conductivity are disposed at positions for contactwith the potential difference measuring probes, and a chip resistor forassociating said electrical conductors with each other and having anelectrical resistance approximately equal to the electrical resistanceproduced across the electrodes of the ion selective electrode pair atthe time electrical conduction is achieved between said electrodes bythe porous bridge through which a sample solution and a referencesolution have spread are supported on the supporting member.

The first-mentioned simple inspection device for an analyzer for ionicactivity measurement in accordance with the present invention, whereinthe supporting member has outer dimensions approximately equal to theouter dimensions of the ionic activity measuring device, can be set at apotential difference measuring section of the analyzer in the samemanner as the slide. After the first-mentioned simple inspection deviceis set at the potential difference measuring section, the potentialdifference measuring probes are moved in the same manner as in thecourse of measurement of a difference in potential, and are contactedwith the electrically conductive member of the simple inspection device,to thereby short-circuit across the probes. As a result, the differencein potential between the probes is found to be zero if the analyzer isnormal. On the other hand, the difference in potential between theprobes does not become zero if the analyzer is not normal, for example,if a contact failure portion, a broken wire, a defective relay, adefective amplifier or the like is present in the electric circuit ofthe analyzer. Therefore, abnormal conditions of the analyzer can befound.

With the second-mentioned simple inspection device in accordance withthe present invention, than abnormal condition of the analyzer can befound in the same manner as mentioned above. However, in this case, aground failure of the electric circuit or the main body of the analyzercan also be found. Specifically, in the case where a ground failurearises within the electric circuit of the analyzer, the aforesaidpotential is caused to fluctuate unstably to the "+" (plus) side or tothe "-" (minus) side by adverse effects of noise upon the electriccircuit. Therefore, the ground failure can be found by investigating thefluctuation of the potential. On the other hand, in the case where thefirst-mentioned simple inspection device is used, the electric circuitis not adversely affected by noise even though a ground failure arises,and therefore the ground failure cannot be found as with thesecond-mentioned simple inspection device.

In the simple inspection device for an analyzer for ionic activitymeasurement in accordance with the present invention, the electricallyconductive member for shortcircuiting across the probes when the probesare contacted with the electrically conductive member, or the highconductivity electrical conductors and the chip resistor for achievingelectrical conduction across the probes via an electrical resistanceapproximately equal to the electrical resistance produced across theelectrodes of the ion selective electrode pair in the course of theusage of the ionic activity measuring device are supported on thesupporting member which can be processed in the same manner as the ionicactivity measuring device. Therefore, with the simple inspection devicefor an analyzer for ionic activity measurement in accordance with thepresent invention, it is possible to determine very simply whether theanalyzer for ionic activity measurement is or is not operating normally.Accordingly, the inspection work by the manufacturer, the serviceman orthe user of the analyzer can be achieved very simply and efficiently.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing an example of an analyzer for ionicactivity measurement to which the simple inspection device in accordancewith the present invention is applied,

FIGS. 2, 3 and 4 are respectively a perspective view, a plan view, and asectional side view showing a major part of the analyzer shown in FIG.1,

FIG. 5 is a sectional side view taken along line V--V of FIG. 3,

FIG. 6 is a sectional side view taken along line VI--VI of FIG. 3,

FIG. 7 is a perspective exploded view showing an example of the slidetype ionic activity measuring device with which the analyzer is used,

FIGS. 8 and 9 are perspective exploded views showing embodiments of thefirst simple inspection device for an analyzer for ionic activitymeasurement in accordance with the present invention, and

FIGS. 10 and 11 are perspective exploded views showing embodiments ofthe second simple inspection device for an analyzer for ionic activitymeasurement in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will hereinbelow be described in further detailwith reference to the accompanying drawings.

First, an analyzer for ionic activity measurement, to which the simpleinspection device in accordance with the present invention is applied,and a slide type ionic activity measuring device used in the analyzerwill be described below. Referring to FIG. 1, outer surfaces of ananalyzer 10 are covered with a cover 11. The cover 11 has with anopening 12 for receiving a slide type ionic activity measuring device(slide) 20 and allowing application of a reference solution and a samplesolution to the slide 20, and an ejection opening 13 for ejecting theslide 20 after potential difference measurement is finished. Theanalyzer 10 is provided with a start pushbutton 14, an ionic activitydisplaying section 15, and an ionic activity recording section 16.

FIGS. 2, 3 and 4 show a mechanism disposed under the section at whichthe opening 12 is formed, and comprising a flat measuring devicesupporting base 30, a pair of side plates 31, 31 secured to oppositeends of the measuring device supporting base 30, and rods 32 32, 33, 33,34, 34 extending in parallel with the measuring device supporting base30 for connecting the side plates 31, 31 with each other. A liquidapplying section 30A is formed at the center of the measuring devicesupporting base 30, and the liquid applying section 30A is disposedbetween a potential difference measuring section 30B and a measuringdevice ejecting section 30C. The measuring device supporting base 30 isdisposed inside the cover 11 so that the liquid applying section 30A ispositioned accurately under the opening 12. The measuring devicesupporting base 30 is provided with a through hole 35 at the potentialdifference measuring section 30B, and a heating plate 36 movable in thevertical direction is disposed in the through hole 35. A slide retainingplate 37 is disposed at a position facing the heating plate 36 in spacedrelation to the surface of the measuring device supporting base 30. Atthe measuring device ejecting section 30C, the measuring devicesupporting base 30 is provided with a slide ejection hole 38 which has asize larger than the slide 20 and which communicates with the ejectionopening 13 of the cover 11 via a slanted passage 39 and an opening 40 inthe side plate 31.

A measuring device holder 42 having a slide setting hole (through hole)41 is disposed on the measuring device supporting base 30. Both ends ofthe measuring device holder 42 are slideably fitted to a pair of therods 32, 32, and therefore the measuring device holder 42 is moveable indirections as indicated by the arrows A and B on the measuring devicesupporting base 30 to sequentially advance to the liquid applyingsection 30A, the potential difference measuring section 30B, and themeasuring device ejecting section 30C. The slide retaining plate 37 isspaced from the surface of the measuring device supporting base 30 by adistance not less than the thickness of the measuring device holder 42so that the measuring device holder 42 can move up to the position abovethe heating plate 36. On the other hand, a holder moving base 43 isdisposed below the measuring device supporting base 30. Both ends of theholder moving base 43 are slideably fitted to a pair of the rods 33, 33,and therefore the holder moving base 43 is moveable in the directions asindicated by the arrows A and B. As shown in FIG. 4, a female threadmember 44 is secured to the lower section of the holder moving base 43and meshed with a drive screw (male thread) 45 disposed in parallel withthe rods 33, 33. The drive screw 45 is rotated clockwise andcounterclockwise by a motor 46, which is secured to the side plate 31,via gears 47 and 48 for moving the holder moving base 43 in thedirections as indicated by the arrows A and B. Connection members 49, 49upwardly projected are formed at opposite end sections of the holdermoving base 43, and magnets 50, 50 are secured to the rear surfaces ofthe connection members 49, 49, i.e. the surfaces thereof facing themeasuring device ejecting section 30C when the holder moving base 43 ispresent in the vicinity of the liquid applying section 30A. On the otherhand, connection members 51, 51 projected downwardly are formed atopposite ends of the measuring device holder 42, and magnets 52, 52facing the magnets 50, 50 are secured to the connection members 51, 51.The magnetic polarity is adjusted so that the magnets 50, 50 adhere tothe magnets 52, 52. Therefore, when the drive screw 45 is rotated tomove the holder moving base 43 in the direction as indicated by thearrow A while the magnets 50, 50 adhere to the magnets 52, 52, themeasuring device holder 42 is pulled by the holder moving base 43 andmoved in the direction as indicated by the arrow A. On the other hand,when the holder moving base 43 is moved in the direction as indicated bythe arrow B, the measuring device holder 42 is pushed by the holdermoving base 43 and moved in the direction as indicated by the arrow B. Acam member 53 acting as a probe movement means is provided at the centerof the holder moving base 43. The cam member 53 projects upwardly andhas a cam surface 53a formed so that it is higher on the side of themeasuring device ejecting section 30C and is lower on the side of thepotential difference measuring section 30B.

The configuration of the section around the heating plate 36 willhereinbelow be described by referring also to FIGS. 5 and 6 which aresectional views taken along line V--V and line VI--VI of FIG. 3. At thepotential difference measuring section 30B, a pair of probe holdersupporting rods 60, 60 are secured to the lower surface of the measuringdevice supporting base 30. The supporting rods 60, 60 are disposed withthe heating plate 36 intervening therebetween, and a probe holder 61 isvertically slideably fitted to the supporting rods 60, 60. The probeholder 61 is stopped from below by washers 62, 62 secured to the lowerends of the supporting rods 60, 60. A pair of heating plate supportingrods 63, 63 are vertically slideably inserted through the probe holder61, and the heating plate 36 is secured to the upper ends of thesupporting rods 63, 63. Springs 64, 64 are disposed in the compressedform around the supporting rods 63, 63 between the heating plate 36 andthe probe holder 61 for urging the heating plate 36 and the probe holder61 to move away from each other. The probe holder 61 thus urged isstopped by washers 65, 65 secured to the lower ends of the heating platesupporting rods 63, 63. The lengths of the supporting rods 60, 60 andthe supporting rods 63, 63 are adjusted so that the upper surface of theheating plate 36 is flush with the surface of the measuring devicesupporting base 30 when the lower surface of the probe holder 61 isstopped by the washers 65, 65 and the washers 62, 62. Also, lower endsof a pair of guide rods 66, 66 are secured to the probe holder 61. Theguide rods 66, 66 are disposed to sandwich the heating plate 36therebetween, and the upper ends of the guide rods 66, 66 areprojectable upwardly of through holes 30d, 30d formed in the measuringdevice supporting base 30. Springs 67, 67 are disposed in the compressedform around the guide rods 66, 66 between the measuring devicesupporting base 30 and the probe holder 61. Therefore, when the probeholder 61 is pushed up from below, it resiliently moves up together withthe heating plate 36 along the supporting rods 60, 60. In the case wherethe heating plate 36 is pushed from above at this time, the probe holder61 is resiliently moved with respect to the heating plate 36.

Also, the probe holder 61 is provided with upwardly projecting probes68a, 68b, 69a, 69b, 70a and 70b for measurement of differences inpotential (by way of example, three pairs of the probes in thisembodiment). The probes 68a, 68b, 69a, 69b, 70a and 70b are projectableupwardly of the heating plate 36 through notches or through holes formedin the heating plate 36. Specifically, when the heating plate 36 and theprobe holder 61 are spaced apart from each other by the largest distanceas shown in FIG. 4 by the effect of the springs 64, 64, the upper endsof the probes 68a, 68b, 69a, 69b, 70a and 70b are positioned inwardly ofthe heating plate 36. When the probe holder 61 is moved with respect tothe heating plate 36 as mentioned above, the upper ends of the probes68a, 68b, 69a, 69b, 70a and 70b are projected upwardly from the surfaceof the heating plate 36. Further, a roller 71 is disposed at the lowersection of the probe holder 61 at the position facing the cam member 53of the holder moving base 43. A through hole 72 is perforated throughthe measuring device supporting base 30 at a position between the liquidapplying section 30A and the potential difference measuring section 30Band a bar code sensor 73 is disposed under the through hole 72.

When measurement of ionic activity is carried out, the measuring deviceholder 42 is in the condition coupled with the holder moving base 43,the motor 46 is operated by being controlled by a known position sensoror a drive control circuit, and the measuring device holder 42 ispositioned at the liquid applying section 30A. As mentioned above, inthis condition, the measuring device holder 42 is positioned preciselyunder the opening 12 of the cover 11. Therefore, it is possible toinsert the slide 20 into the slide setting hole 41 of the measuringdevice holder 42 via the opening 12.

The slide 20 may be of the type as described in Japanese UnexaminedPatent Publication No. 58(1983)-211648, Japanese Patent Application Nos.60(1985)-148564 and 60(1985)180358, and Japanese Utility ModelApplication No. 60(1985)-204699. The configuration of the slide 20 willnow be described briefly with reference to FIG. 7. The slide 20comprises an upper frame half 400 and a lower frame half 500 formed of aplastic material. Between the upper frame half 400 and the lower framehalf 500, there are housed an ion selective electrode pair 101comprising ion selective electrodes 111 and 121 having ion selectivelayers of the same type on their surfaces and electrically isolated fromeach other, an ion selective electrode pair 102 comprising ion selectiveelectrodes 112 and 122 having ion selective layers of the same type ontheir surfaces and electrically isolated from each other, an ionselective electrode pair 103 comprising ion selective electrodes 113 and123 having ion selective layers of the same type on their surfaces andelectrically isolated from each other, a water-impermeable member layer200 having adhesive layers on both surfaces, and a pair of porous liquiddistributing members 310 and 320 formed of cotton and regeneratedcellulose fiber non-woven fabrics having continuous pores.

The upper frame half 400 is provided with a pair of liquid feed holes410 and 420, and a recess 450 extending across the liquid feed holes 410and 420. A porous bridge 600 formed of polyethylene terephthalate fibersor the like is housed and secured in the recess 450. The depth of therecess 450 is set to such a value that the bridge 600 does not projectfrom the upper surface of the upper frame half 400.

The water-impermeable member layer 200 disposed below the upper framehalf 400 with the ion selective electrode pairs 101, 122 and 103intervening therebetween is provided with through holes (liquid descentpassages) 210 and 220 matched with the liquid feed holes 410 and 420,and through holes (liquid ascent passages) 211, 212, 213, 221, 222 and223 respectively matched with portions of ion selective layer regions ofthe ion selective electrodes 111, 112, 113, 121, 122 and 123. Under thewater-impermeable member layer 200, the porous liquid distributingmember 310 is disposed to match with the through holes 210, 211, 212 and213, and the porous liquid distributing member 320 is disposed to matchwith the through holes 220, 221, 222 and 223. The lower frame half 500is provided with recesses (horizontal liquid passages) 510 and 520having shapes capable of housing therein the porous liquid distributingmembers 310 and 320. Also, the upper frame half 400, thewater-impermeable member layer 200, and the lower frame half 500 arerespectively provided with a pair of through holes (air dischargingholes) 430 and 440, a pair of through holes 230 and 240, and a pair ofthrough holes 530 and 540, which constitute air discharging holesextending through the whole slide 20. The ion selective electrode pairs101, 102, and 103 are disposed with their ion selective layers facingdown, and terminal sections of these ion selective electrode pairs areexposed at the lower surface of the slide 20 from a pair of cutawaysections 250 and 260 of the water-impermeable member layer 200, and apair of cutaway sections 550 and 560 of the lower frame half 500.

In this slide 20, the ion selective electrode pairs 101, 102, and 103are respectively provided with the ion selective layers selectivelyresponding to, for example, Cl⁻, K⁺, and Na⁺ ions. A reference solutioncontaining these ions whose ionic activity values are known is appliedto the liquid feed hole 410, and a sample solution whose ionic activityvalues are unknown is applied to the liquid feed hole 420. The appliedreference solution permeates through the porous liquid distributingmember 310 via the liquid descent passage 210, and then passes throughthe liquid ascent passages 211, 212 and 213 to the ion selective layersof the ion selective electrodes 111, 112 and 113. The applied samplesolution permeates through the porous liquid distributing member 320 viathe liquid descent passage 220, and then passes through the liquidascent passages 221, 222 and 223 to the ion selective layers of the ionselective electrodes 121, 122 and 123. Also, the reference solution andthe sample solution come into contact with each other near the center ofthe bridge 600, thereby giving rise to electrical conductiontherebetween. As a result, differences in potential corresponding to thedifferences in ionic activity of the Cl⁻, K⁺, and Na⁺ ions between thereference solution and the sample solution are given rise to between theion selective electrodes 111 and 121, between the ion selectiveelectrodes 112 and 122, and between the ion selective electrodes 113 and123. Accordingly, when potential measuring probes are inserted frombelow the cutaway sections 550 and 560 until they contact the terminalsections of the ion selective electrodes and the difference in potentialacross each ion selective electrode pair is measured, it is possible tomeasure the ionic activity of each ion in the sample solution.

The slide 20 is inserted into the slide setting hole 41 with the upperframe half 400 facing up, and the reference solution and the samplesolution are applied respectively to the liquid feed holes 410 and 420by use of, for example, a dual pipette. When the start pushbutton 14 asshown in FIG. 1 is depressed, the motor 46 is operated, and the holdermoving base 43 is moved in the direction as indicated by the arrow A.The measuring device holder 42 is also moved towards the potentialdifference measuring section 30B by being pulled by the holder movingbase 43, and comes into contact with a stopper 90. Thus the slide 20held on the measuring device holder 42 is stopped at a predeterminedposition facing the heating plate 36. The motor 46 continues to operate,and the holder moving base 43 is further moved by a predetermineddistance. At this time, since movement of the measuring device holder 42is restrained by the stopper 90, the magnets 50, 50 are separated fromthe magnets 52, 52, and the holder moving base 43 is moved alone asmentioned above. When the holder moving base 43 is thus moved, the camsurface 53a of the cam member 53 comes into contact with the roller 71of the probe holder 61, and pushes the probe holder 61 up. As a result,the heating plate 36 is pushed up as mentioned above, and pushes up andfixes the slide 20, which is held on the measuring device holder 42, tothe slide retaining plate 37. At this time, as the probe holder 61 ismoved up, the guide rods 66, 66 are projected upwardly from themeasuring device supporting base 30, inserted into guide holes 91, 91 ofthe measuring device holder 42, and adjust the position of the measuringdevice holder 42, and consequently the position of the slide 20, at apredetermined position. When the slide 20 has been pushed against theslide retaining plate 37 in this manner, upward movement of the heatingplate 36 is restrained. The probe holder 61 is further pushed up by apredetermined distance, and the probes 68a, 68b, 69a, 69b, 70a and 70bare thereby projected upwardly of the surface of the heating plate 36.The probes 68a and 68b thus projected up are inserted into the cutawaysections 550 and 560 of the slide 20 from below, and come into contactwith the ion selective electrodes 111 and 121. Also, the probes 69a and69b are inserted into the cutaway sections 550 and 560 from below, andcome into contact with the ion selective electrodes 112 and 122. In thesame manner, the probes 70a and 70b are inserted into th cutawaysections 550 and 560 from below, and contact the ion selectiveelectrodes 113 and 123.

In this condition, the motor 46 is stopped, and then the slide 20 isheated to a predetermined temperature by the seating plate 36. After apredetermined time has elapsed, differences in potential across the ionselective electrode pair 101, across the ion selective electrode pair102, and across the ion selective electrode pair 103 are measured by useof known potential difference measuring circuits (not shown) connectedto the probes 68a, 68b, 69a, 69b, 70a and 70b. As mentioned above, ionicactivity values of the Cl⁻, K⁺ and Na⁺ ions are measured by measuringthe differences in potential. As shown in FIG. 1, the ionic activityvalues thus measured are indicated on the displaying section 15, orrecorded in recording paper 17 at the recording section 16. The bar codeof the slide 20 subjected to the measurement of differences in potentialis read out by the bar code sensor 73, and the ionic activity values aredisplayed or recorded together with the identification code of the slide20.

When measurement of the differences in potential is finished, the motor46 is rotated in the reverse direction to move the holder moving base 43in the direction as indicated by the arrow B. Thus the cam member 53 isgradually moved away from the roller 71 of the probe holder 61, and theprobe holder 61 is moved down. Therefore, the probes 68a, 68b, 69a, 69b,70a and 70b are first separated from the slide 20, the guide rods 66, 66are moved down from the guide holes 91, 91 of the measuring deviceholder 42, and the heating plate 36 is moved down to the position whereits surface is matched with the surface of the measuring devicesupporting base 30. Since the motor 46 continues to be operated and theholder moving base 43 continues to be moved, the connection members 49,49 of the holder moving base 43 push the connection members 51, 51 viathe magnets 50, 50 and the magnets 52, 52, and the measuring deviceholder 42 is moved in the direction as indicated by the arrow B.Accordingly, the slide 20 for which the potential difference measurementhas been finished is sent by the measuring device holder 42 from thepotential difference measuring section 30B to the liquid applyingsection 30A. The motor 46 is operated until the measuring device holder42 comes to the position above the measuring device ejecting section30C. When the measuring device holder 42 comes to the position above themeasuring device ejecting section 30C, the slide 20 held on themeasuring device holder 42 is allowed to fall into the slide ejectionhole 38. The slide 20 is ejected from the ejection opening 13 via thepassage 39. Then, the motor 46 is rotated reversely to send themeasuring device holder 42 to the liquid applying section 30A, and themeasuring device holder 42 is stopped at the liquid applying section 30Aand waits for the next applying operation.

Embodiments of the simple inspection device for an analyzer for ionicactivity measurement in accordance with the present invention will bedescribed hereinbelow.

FIG. 8 shows an embodiment of the first simple inspection device for ananalyzer for ionic activity measurement in accordance with the presentinvention. As shown in FIG. 8, a simple inspection device 1 comprises anupper mount 2 and a lower mount 3 constituting a supporting member, anda metal plate 4 secured between the upper mount 2 and the lower mount 3.The upper mount 2 and the lower mount 3 have outer dimensionsapproximately equal to the outer dimensions of the upper frame half 400and the lower frame half 500 of the slide 20, and are formed of, forexample, a plastic material. The upper frame half 400 and the lowerframe half 500 may be utilized respectively as the upper mount 2 and thelower mount 3. On the other hand, the metal plate 4 is formed of amaterial which is corrosion resistant and highly durable, for example,stainless steel. In this embodiment, the metal plate 4 has length andwidth dimensions approximately equal to the length and width dimensionsof the upper mount 2 and the lower mount 3. Also, the lower mount 3 isprovided with through holes 3a, 3b, 3c, 3d, 3e and 3f at positionsrespectively corresponding to the through holes 211, 212, 213, 221, 222and 223 of the water-impermeable member layer 200 of the slide 20.

In the course of inspecting whether the analyzer 10 is or is notoperating correctly, the simple inspection device 1 having the aforesaidconfiguration is inserted into the slide setting hole 41 instead of theslide 20. In this case, since the upper mount 2 and the lower mount 3have the aforesaid outer dimensions, the simple inspection device 1 issnuggly accommodated in the slide setting hole 41. At this time, thesimple inspection device 1 is set in the slide setting hole 41 with theupper mount 2 facing up. Then, the start pushbutton 14 is depressed tomove the holder moving base 43 so that it cans up the probe holder 61 inthe same manner as in the course of measurement of ionic activity. As aresult, the probes 68a, 68b, 69a, 69b, 70a and 70b are projectedupwardly. The probes 68a and 68b pass through the through holes 3a and3b of the lower mount 3, the probes 69a and 69b pass through the throughholes 3b and 3e of the lower mount 3, and the probes 70a and 70b passthrough the through holes 3c and 3f of the lower mount 3. Thus theprobes 68a, 68b, 69a, 69b, 70a and 70b contact the metal plate 4.Therefore, the probes are short-circuited across the probes 68a and 68b,across the probes 69a and 69b, and across the probes 70a and 70b.

In the case where the electric circuit of the analyzer is normal, thedifference in potential between each pair of the probes is equal to zeroupon short-circuiting across the probes as mentioned above. The zerovalue of the difference in potential is indicated on the displayingsection 15, and the inspector can confirm that the analyzer 10 iscapable of operating normally based on the displayed value.

On the other hand, in the case where the analyzer is operatingabnormally, for example, in the case where a contact failure portion, abroken wire, a defective relay, a defective amplifier or the like ispresent in the electric circuit of the analyzer, the difference inpotential between the probes does not become zero upon short-circuitingthereof. Therefore, the inspector can confirm that a problem has arisenwith the analyzer 10 based on the value indicated on the displayingsection 15.

Another embodiment of the first simple inspection device for an analyzerfor ionic activity measurement in accordance with the present inventionwill now be described with reference to FIG. 9. In FIG. 9, similarelements are numbered with the same reference numerals with respect toFIG. 8. A simple inspection device 5 shown in FIG. 9 comprises metalplates 6, 7 and 8 disposed independently of each other, instead of thelarge metal plate 4 shown in FIG. 8. The metal plates 6, 7 and 8 aresecured at positions corresponding respectively to the ion selectiveelectrode pairs 101, 102 and 103 of the slide 20. The simple inspectiondevice 5 having the aforesaid configuration is used for inspection ofthe analyzer 10 in the same manner as the simple inspection device 1shown in FIG. 8. With the simple inspection device 5, the normal orabnormal condition of the analyzer 10 can be confirmed in the samemanner as the simple inspection device 1 shown in FIG. 8. With thesimple inspection device 5 wherein the metal plates 6, 7 and 8 forrespectively short-circuiting across the probes 68a and 68b, across theprobes 69a and 69b, and across the probes 70a and 70b are disposedindependently of each other and electrically isolated from each other,incorrect wire connections among the potential difference measuringprobes (68a, 68b, 69a, 69b, 70a, and 70b) and relays, and contactfailures and broken wires in the three circuit lines can be confirmedfor each of the circuit lines.

The metal plates 6, 7 and 8 may be formed of stainless steel or the likeas mentioned above, or may be formed of copper alloy plates or the likehaving the surface plated with tin or gold in order to increase theanticorrosion effects and to improve the electrical contact condition.This modification applies also to the metal plate 4 shown in FIG. 8.

An embodiment of the second simple inspection device for an analyzer forionic activity measurement in accordance with the present invention willhereinbelow be described with reference to FIG. 10. A simple inspectiondevice 1' shown in FIG. 10 comprises a metal plate 4A facing the throughholes 3a, 3b and 3c, and a metal plate 4B facing the through holes 3d,3e and 3f. The metal plates 4A and 4B may be formed of stainless steelor the like as mentioned above, or may be formed of copper alloy plateshaving the surface plated with gold or the like. The metal plate 4A and4B are associated with each other by a thin chip resistor 4C i.e. aresistor in form of a chip.

At the time a reference solution and a sample solution are applied indrops to the slide 20 and liquid junction is achieved between thereference solution and the sample solution near the middle of the bridge600, the electrical resistance across the ion selective electrodes 111and 121 for the Cl⁻ ion is approximately 100 kΩ, for example. Also, atthis time, the electrical resistance across the ion selective electrodes112 and 122 for the K⁺ ion is approximately 10MΩ, and the electricalresistance across the ion selective electrodes 113 and 123 for the Na⁺ion is approximately 1MΩ. Accordingly, as the chip resistor 4C, aresistor of approximately 1MΩ, which value is an intermediate valueamong the aforesaid three resistance values, is utilized.

Also, with the simple inspection device 1', an abnormality of theanalyzer 10 can be found in the same manner as with the simpleinspection device 1 or the simple inspection device 5.

As mentioned above, the electrical resistance across the metal plates 4Aand 4B is adjusted to a value close to the electrical resistance valuesproduced across the ion selective electrodes 111 and 121, across the ionselective electrodes 112 and 122, and across the ion selectiveelectrodes 113 and 123 at the time of measurement of ionic activity. Inthe case where a ground failure arises with the electric circuit or themain body of the analyzer 10, the electric circuit is adversely affectedby noise, and the potential value indicated on the displaying section 15fluctuates unstably to the "+" (plus) side or to the "-" (minus) side.Therefore, the ground failure can be found by investigating thefluctuation of the potential value indicated on the displaying section15.

Another embodiment of the second simple inspection device for ananalyzer for ionic activity measurement in accordance with the presentinvention will hereinbelow be described with reference to FIG. 11. Asimple inspection device 5' shown in FIG. 11 comprises metal plates 6Aand 6B respectively facing the through holes 3a and 3d, metal plates 7Aand 7B respectively facing the through holes 3b and 3e, and metal plates8A and 8B respectively facing the through holes 3c and 3f. The metalplates 6A and 6B are associated with each other by a chip resistor 6C,the metal plates 7A and 7B are associated with each other by a chipresistor 7C, and the metal plates 8A and 8B are associated with eachother by a chip resistor 8C. The electrical resistance values of thechip resistors 6C, 7C and 8C are adjusted respectively to approximately100 kΩ, 10MΩ and 1MΩ to match the electrical resistance values producedacross the ion selective electrodes 111 and 121, across the ionselective electrodes 112 and 122, and across the ion selectiveelectrodes 113 and 123 at the time of measurement of ionic activity.

With the simple inspection device 5' wherein the electrical resistancevalues across the metal plates 6A and 6B, across the metal plates 7A and7B, and across the metal plates 8A and 8B are adjusted to the levels asmentioned above, the level of the effects of noise which the threecircuit lines having the probes 68a and 68b, the probes 69a and 69b, andthe probes 70a and 70b as the detection terminals receive in the courseof inspection of the analyzer is close to the extent of effects of noisearising in the course of measurement of ionic activity. Accordingly,with the simple inspection device 5', inspection of the analyzer can becarried out more accurately.

Though the analyzer 10 constituted such that the slide 20 isautomatically sent to and ejected from the potential differencemeasuring section is taken as an example, the simple inspection devicefor an analyzer for ionic activity measurement in accordance with thepresent invention is not limited to the use for the analyzer of thistype, and is applicable also to an analyzer so constituted that theslide 20 is manually sent to and ejected from the potential differencemeasuring section.

We claim:
 1. An inspection device for an analyzer, which inspectiondevice is used for testing the functions of the analyzer, and whichanalyzer measures ionic activity by use of an ionic activity measuringdevice provided with at least one ion selective electrode pair forgenerating an electric potential corresponding to ionic activity of apredetermined ion and a porous bridge connecting the electrodes of theion selective electrode pair with each other, a plurality of potentialdifference measuring probes mounted for movement towards and away fromrespective electrodes of the ionic activity measuring device for contactrespectively with the electrodes of the ion selective electrode pair, tothereby measure a difference in potential between the electrodes, and ameasurement device holder for removably supporting said ionic activitymeasuring device, said inspection device for said analyzer beingmountable on said holder in lieu of said ionic activity measuring deviceand comprising:(i) electrically non-conductive supporting meansremovably supported by said measurement device holder (ii) a pair ofelectrical conductors supported on said supporting means and disposed atpositions for contacting respective potential difference measuringprobes, and (iii) a resistor in the form of a chip for bridging saidelectrical conductors said supporting means being formed with accessmeans for allowing said electrically conductive member to be contactedby said probes.
 2. An inspection device as defined in claim 1 whereineach of said electrical conductors is composed of a metal having asurface plated with tin or gold.
 3. An inspection device as defined inclaim 1 wherein said supporting means is composed of an upper mount anda lower mount supporting said electrical conductors and said resistorbridging therebetween, and wherein said access means comprisesthrough-holes formed in one of said mounts and passage of the probestherethrough for contact with said potential difference between saidconductors via said resistor.